Tesla says the Model X passed 15 seat-strength tests before failing a 16th designed to meet more stringent European standards.

The company has received no reports of seat failures from customers. But Tesla says customers shouldn’t use the third row until it’s repaired.

Tesla will replace the seat backs in the affected vehicles. Customers will be notified when parts are available; the repair takes about two hours. Tesla says it will take five weeks to make parts for the repairs.